Nail brush



FIG. 1 is a front end view of a nail brush showing my new design;

FIG. 2 is a left side elevational view thereof, the right side being a mirror image;

FIG. 3 is a rear end view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a left side elevational view of a modification of a nail brush, and

FIG. 7 is a bottom plan view thereof. 

The ornamental design for a nail brush, as shown and described. 